The present invention relates to a cleaning apparatus for cleaning a substrate, such as a semiconductor wafer, by using a cleaning member, while the substrate is held and rotated and a cleaning liquid is supplied onto the substrate. The present invention also relates to the cleaning member used in the above-mentioned cleaning apparatus.
FIG. 1 shows an arrangement of a substrate cleaning apparatus of the above-mentioned type. As shown in FIG. 1, the substrate cleaning apparatus comprises a substrate holding/rotating mechanism 10 for holding and rotating a substrate Wf and a cleaning member mount mechanism 20 on which a cleaning member 21 is mounted. The substrate holding/rotating mechanism 10 comprises a plurality of arms 12 (four in FIG. 1) each having a chuck 11 attached thereto for holding the substrate Wf in a horizontal position. The arms 12 are provided to be integral with a base mount 13 which is adapted to be rotated by a rotary shaft 14 in a direction indicated by an arrow A.
The cleaning member mount mechanism 20 has a pivot arm 23. A rotary shaft 22 is connected to a forward end of the pivot arm 23 and the cleaning member 21 is attached to a lower end of the rotary shaft 22. The rotary shaft 22 is adapted to be rotated by a rotating mechanism (not shown) in a direction indicated by an arrow B, thus rotating the cleaning member 21 in the same direction. Further, a pivot shaft 24 is connected to a rear end portion of the pivot arm 23 and adapted to pivotally move the pivot arm 23 in directions indicated by arrows C. The pivot shaft 24 is also adapted to vertically move the pivot arm 23 in directions indicated by arrows D.
As shown in FIG. 2(a), the cleaning member 21 comprises a cleaning element 21a made of a sponge and a holding element 21b for holding the cleaning element 21a. This cleaning member 21 is fixed to the rotary shaft 22 and the cleaning element 21a is brought into abutment with an upper surface of the substrate Wf. At the same time, a cleaning liquid is supplied from a nozzle 25 onto the substrate Wf and the rotary shaft 22 is rotated, while the pivot arm 23 is pivotally moved, to thereby clean the upper surface of the substrate Wf. When a force of rotation of the rotary shaft 22 and a force of pivotal movement of the pivot arm 23 are transmitted to the cleaning element 21a, the cleaning element 21a can be detached from the holding element 21b as shown in FIG. 2(b), due to the effect of frictional force generated between the cleaning element 21a and the substrate Wf. This deteriorates a cleaning performance and, if such detachment of the cleaning element is not detected, the apparatus continues to produce insufficiently cleaned products.